Study On Preparation And Heat Transfer Characteristics Of Microencapsulated Phase Change Material Suspension

As a new type of heat transfer function fluid,phase-change microcapsule suspension(MPCMS)has attracted more and more researchers’attention because of its advantages in energy storage and heat transfer.In order to explore the characteristics of MPCMS in the practical application of engineering,this paper makes an experimental study and theoretical analysis of MPCMS heat exchange.First of all,with modified formaldehyde resin as the wall material,paraffin phase change microcapsule suspension was prepared.Based on the calculation of the particle density of the base and microcapsules,the proportion of water and propanol in the base solution was reasonable.The reasonable proportion of water and n-propanol in the base solution is reasonable,and the stratification problem of the suspensions that due to density difference is solved.The physical properties of MPCMS were tested by experimental test.The influences of the mass concentration of MPCMS on the heat transfer parameters such as specific heat capacity,thermal conductivity and overall viscosity were analyzed.And we can obtain the thermal conductivity and viscosity of MPCMS.The second,the heat exchange experiment platform was set up,and MPCMS was used as a heat exchange medium for heat exchange experiment.Collect relevant data in the experiment process.Through the processing of experimental data,In this paper,we calculate the parameters such as Nusselt number(Nu),Stefan number(Ste),heat transfer coefficient(h_x)and other parameters of MPCMS in the heat transfer process.By studying the heat exchange characteristics of MPCMS under different working conditions,and different mass concentration,the heat storage curve and heat transfer characteristic curve of MPCMS were obtained.At the same time,by comparing the convection heat transfer under different Reynolds number(Re),the effect of Re on the enhanced heat transfer of MPCMS was studied,and the convective heat transfer characteristic curve of MPCMS was obtained under different Reynolds number.The last,by means of theoretical research,the mechanism of MPCMS enhanced heat exchange is preliminarily analyzed.The apparent specific heat capacity of phase-change material in MPCMS with different mass concentration is calculated.As the result show that in this paper,the relationship between MPCMS concentration and apparent specific heat capacity is obtained.Theoretical analysis and research on the effective thermal conductivity of MPCMS in the heat exchange and the mechanism of multiphase functional fluid heat transfer were studied.Through the solution of the convective heat transfer control equation,the strengthening mechanism of MPCMS is clarified,and the scientific and reliability of the experimental results are proved theoretically.